Finding the Fourth Proportional to 1,078.93, 1,488.53 and 636.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.93 : 1,488.53 = 636.61 : x
2. Step 2: Convert to fraction form
   1,078.93/1,488.53 = 636.61/x
3. Step 3: Cross multiply
   1,078.93x = 1,488.53 × 636.61
4. Step 4: Simplify right side
   1,078.93x = 947,607.23
5. Step 5: Solve for x
   x = 947,607.23/1,078.93
6. Step 6: Final answer
   x = 878.29